docs(react-query): ensure suspense example fallback renders correctly (#9119)

The previous suspense example incorrectly rendered null instead of the
fallback UI. This change moves the null check outside the Suspense
component to ensure the fallback is displayed as expected.

Fixes #9019

Author: xxziiko

examples/react/suspense/src/index.tsx

@@ -70,18 +70,18 @@ function Example() {
             )}
             onReset={reset}
           >
-            <React.Suspense fallback={<h1>Loading projects...</h1>}>
-              {showProjects ? (
-                activeProject ? (
+            {showProjects ? (
+              <React.Suspense fallback={<h1>Loading projects...</h1>}>
+                {activeProject ? (
                   <Project
                     activeProject={activeProject}
                     setActiveProject={setActiveProject}
                   />
                 ) : (
                   <Projects setActiveProject={setActiveProject} />
-                )
-              ) : null}
-            </React.Suspense>
+                )}
+              </React.Suspense>
+            ) : null}
           </ErrorBoundary>
         )}
       </QueryErrorResetBoundary>